Composition to Reduce Adhesion Between a Conformable Region and a Mold

ABSTRACT

An imprint lithography mold assembly includes a mold having a surface, a substrate having a surface, and a polymerizable composition disposed between the surface of the mold and the surface of the substrate. The polymerizable composition includes a bulk material and a non-ionic surfactant having a first end and a second end. The first end of the non-ionic surfactant has an affinity for the bulk material, and the second end of the non-ionic surfactant is fluorinated.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a Continuation of U.S. patent applicationSer. No. 11/837,757 filed on Aug. 13, 2007 and a Continuation-in-Part ofU.S. patent application Ser. No. 11/459,797 filed on Jul. 25, 2006, bothof which are hereby incorporated by reference herein.

U.S. patent application Ser. No. 11/459,797 is a Continuation of U.S.Pat. No. 7,157,036 filed on Jun. 17, 2003, which is hereby incorporatedby reference herein.

U.S. patent application Ser. No. 11/837,757 is a Continuation of U.S.Pat. No. 7,307,118. U.S. Pat. No. 7,307,118 is a Continuation-in-Part ofU.S. patent application Ser. No. 11/012,374 (now abandoned), and is alsoa Divisional of U.S. patent application Ser. No. 11/068,397 (nowabandoned). U.S. patent application Ser. No. 11/068,397 is aContinuation-in-Part of U.S. patent application Ser. No. 11/012,374, aContinuation-in-Part of U.S. patent application Ser. No. 11/012,375 (nowabandoned), and claims priority to U.S. Provisional Application No.60/631,029. All of these applications are hereby incorporated byreference herein.

U.S. patent application Ser. No. 11/837,757 is also a Continuation ofU.S. patent application Ser. No. 11/068,174. U.S. patent applicationSer. No. 11/068,174 is a Continuation-in-Part of U.S. patent applicationSer. Nos. 11/012,374 and 11/012,375 and a Divisional of U.S. patentapplication Ser. No. 11/068,397. U.S. patent application Ser. No.11/068,397 is a Continuation-in-Part of U.S. patent application Ser. No.11/012,374, a Continuation-in-Part of U.S. patent application Ser. No.11/012,375, and claims priority to U.S. Provisional Application No.60/631,029. All of these applications are hereby incorporated herein byreference.

U.S. patent application Ser. No. 11/837,757 is also a Continuation ofU.S. patent application Ser. No. 11/244,428. U.S. patent applicationSer. No. 11/244,428 is a Continuation of U.S. application Ser. No.11/068,397 and a Continuation of U.S. application Ser. No. 10/763,885(now abandoned). U.S. patent application Ser. No. 11/068,397 is aContinuation-in-Part of U.S. patent application Ser. No. 11/012,374, aContinuation-in-Part of U.S. patent application Ser. No. 11/012,375, andclaims priority to U.S. Provisional Application No. 60/631,029. All ofthese applications are hereby incorporated by reference herein.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

The United States government has a paid-up license in this invention andthe right in limited circumstance to require the patent owner to licenseothers on reasonable terms as provided by the terms of 70NANB4H3012awarded by National Institute of Standards (NIST) ATP Award.

BACKGROUND OF THE INVENTION

The field of invention relates generally to nano-fabrication ofstructures. More particularly, the present invention is directed tocompositions suited for patterning substrates in furtherance of theformation of structures employing imprint lithographic processes.

Nano-scale fabrication involves the fabrication of very smallstructures, e.g., having features on the order of one nano-meter ormore. A promising process for use in nano-scale fabrication is known asimprint lithography. Exemplary imprint lithography processes aredescribed in detail in numerous publications, such as United Statespublished patent application 2004-0065976 filed as U.S. patentapplication Ser. No. 10/264,960, entitled “Method and a Mold to ArrangeFeatures on a Substrate to Replicate Features having Minimal DimensionalVariability”; United States published patent application 2004-0065252filed as U.S. patent application Ser. No. 10/264,926, entitled “Methodof Forming a Layer on a Substrate to Facilitate Fabrication of MetrologyStandards”; and United States published patent application 2004-0046271filed as U.S. patent application Ser. No. 10/235,314, entitled “Methodand a Mold to Arrange Features on a Substrate to Replicate Featureshaving Minimal Dimensions Variability”; all of which are assigned to theassignee of the present invention.

Referring to FIG. 1, the basic concept behind imprint lithography isforming a relief pattern on a substrate that may function as, interalia, an etching mask so that a pattern may be formed into the substratethat corresponds to the relief pattern. System 10 employed to form therelief pattern includes stage 11 upon which substrate 12 is supported.Template 14 has a mold 16 with a patterning surface 18 thereon.Patterning surface 18 may be substantially smooth and/or planar, or maybe patterned so that one or more recesses are formed therein. Template14 is coupled to imprint head 20 to facilitate movement of template 14.Fluid dispense system 22 is coupled to be selectively placed in fluidcommunication with substrate 12 so as to deposit polymerizable material24 thereon. Source 26 of energy 28 is coupled to direct energy 28 alonga path 30. Imprint head 20 and stage 11 are configured to arrange mold16 and substrate 12, respectively, to be in superimposition, anddisposed in path 30. Either imprint head 20, stage 11, or both vary adistance between mold 16 and substrate 12 to define a desired volumetherebetween that is filled by polymerizable material 24.

Typically, polymerizable material 24 is disposed upon substrate 12before the desired volume is defined between mold 16 and substrate 12.However, polymerizable material 24 may fill the volume after the desiredvolume has been obtained. After the desired volume is filled withpolymerizable material 24, source 26 produces energy 28, which causespolymerizable material 24 to solidify and/or cross-link, formingpolymeric material conforming to the shape of the substrate surface 24and mold surface 18. Control of this process is regulated by processor32 that is in data communication with stage 11, imprint head 20, fluiddispense system 22, and source 26, operating on a computer readableprogram stored in memory 34.

An important characteristic with accurately forming the pattern in thepolymerizable material is to reduce, if not prevent, adhesion to themold of the polymeric material, while ensuring suitable adhesion to thesubstrate. This is referred to as preferential release and adhesionproperties. In this manner, the pattern recorded in the polymericmaterial is not distorted during separation of the mold therefrom. Priorart attempts to improve the release characteristics employ a releaselayer on the surface of the mold. The release layer is typicallyhydrophobic and/or has low surface energy. The release layer adheres tothe mold. Providing the release layer improves release characteristicsby minimizing distortions in the pattern recorded into the polymericmaterial that are attributable to mold separation. This type of releaselayer is referred to, for purposes of the present discussion, as an apriori release layer, i.e., a release layer that is solidified to themold.

Another prior art attempt to improve release properties is described byBender et al. in Multiple Imprinting in UV-based NanoimprintLithography: Related Material Issues, Microeletronic Engineering 61-62(2002), pp. 407-413. Specifically, Bender et al. employ a mold having ana priori release layer in conjunction with a fluorine-treated UV curablematerial. To that end, a UV curable layer is applied to a substrate byspin-coating a 200 cPs UV curable fluid to form a UV curable layer. TheUV curable layer is enriched with fluorine groups to improve the releaseproperties.

A priori release layers, however, typically have a limited operationallife. As a result, a single mold may be coated multiple times with an apriori release layer. This can result in several hours of down-time fora given mold, reducing throughput. Additionally, the molecular structureof the a priori release layer may limit the minimization of the minimumfeature dimension that is printed.

There is a need, therefore, to improve the preferential release andadhesion properties of a mold employed in imprint lithography processes.

SUMMARY

An imprint lithography mold assembly includes a mold having a surface, asubstrate having a surface, and a polymerizable composition disposedbetween the surface of the mold and the surface of the substrate. Thepolymerizable composition includes a bulk material and a non-ionicsurfactant having a first end and a second end. The first end of thenon-ionic surfactant has an affinity for the bulk material, and thesecond end of the non-ionic surfactant is fluorinated.

Compositions described herein feature improved preferential adhesion andrelease characteristics with respect to a substrate and a mold havingimprinting material disposed therebetween. The compositions facilitatebifurcation of the imprinting material into a surfactant-component-richsub-portion and a surfactant-component-depleted sub-portion locatedbetween said surfactant-component-rich sub-portion and said substrate.This surfactant-component-rich sub-portion attenuates the adhesionforces between the mold and the imprinting material, once solidified.Specifically, the surfactant component has opposed ends. In the liquidphase, one of the opposed ends has an affinity for the bulk material.The remaining end has a fluorine component. As a result of the affinityfor the bulk material, the surfactant component is orientated so thatthe fluorine component extends from an air-liquid interface defined bythe imprinting material and the surrounding ambient. Upon solidificationof the imprinting material, a lamella remains, positioned between thesolidified imprinting material and the mold. The lamella results fromthe presence and location of the fluorine components in thesurfactant-component-rich sub-portion. As a result, it has beendetermined that several materials could be employed in imprintlithography processes. Specifically, the bulk materials and surfactantcomponent combinations employed in a composition of imprinting materialare selected to provide the desired preferential adhesion and releaseproperties. Exemplary compositions include an initiator component andcompounds selected from a set of compounds consisting essentially ofvinyl ethers, methacrylates, acrylates, thiol-enes, epoxies, as well asa surfactant component, having opposed ends, one of which has anaffinity for said bulk material and the remaining end having a fluorinecomponent. These and other embodiments are described herein.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a lithographic system in accordance withthe prior art;

FIG. 2 is a simplified elevation view of a template and imprint materialdisposed on a substrate in accordance with the present invention;

FIG. 3 is a simplified elevation view of the template and substrateshown in FIG. 2, with the imprinting material being shown as patternedand solidified;

FIG. 4 is a detailed view of the droplets of imprint material, shown inFIG. 2, showing the bifurcation of the droplets into surfactant-richregions and surfactant-depleted regions;

FIG. 5 is a detailed view of a layer of imprinting material, depositedemploying spin-on techniques, showing the bifurcation of the layer intosurfactant-rich regions and surfactant-depleted regions;

FIG. 6 is a cross-sectional view of the template contacting imprintingmaterial, deposited as shown in either FIG. 4 or 5, demonstrating theformation of the weak boundary lamella between solidified imprintingmaterial and a template; and

FIG. 7 is a cross-sectional view of the template shown in FIG. 6 havinga layer of surfactant containing solution disposed thereon, inaccordance with the present invention.

FIG. 8 is a graph showing separation data concerning bulk material A1;

FIG. 9 is a graph showing separation data concerning bulk material A2;

FIG. 10 is a graph showing separation data concerning bulk material A3;

FIG. 11 is a graph showing separation data concerning bulk material A4;

FIG. 12 is a graph showing separation data concerning bulk material A5;

FIG. 13 is a graph showing separation data concerning bulk material A6;and

FIG. 14 is a graph showing separation data concerning bulk material A7.

DETAILED DESCRIPTION

Referring to FIGS. 1 and 2, a mold 36, in accordance with the presentinvention, may be employed in system 10, and may define a surface havinga substantially smooth or planar profile (not shown). Alternatively,mold 36 may include features defined by a plurality of spaced-apartrecessions 38 and protrusions 40. The plurality of features defines anoriginal pattern that is to be transferred into substrate 42. Substrate42 may comprise a bare wafer or a wafer with one or more layers disposedthereon. To that end, reduced is a distance “d” between mold 36 andsubstrate 42. In this manner, the features on mold 36 may be imprintedinto a conformable region of substrate 42, such as an imprintingmaterial disposed on a portion of surface 44 that presents asubstantially planar profile. It should be understood that theimprinting material may be deposited using any known technique, e.g.,spin-coating, dip coating and the like. In the present example, however,the imprinting material is deposited as a plurality of spaced-apartdiscrete droplets 46 on substrate 42. Imprinting layer 34 is formed froma composition that may be selectively polymerized and cross-linked torecord the original pattern therein, defining a recorded pattern.

Specifically, the pattern recorded in the imprinting material isproduced, in part, by interaction with mold 36, e.g., electricalinteraction, magnetic interaction, thermal interaction, mechanicalinteraction and the like. In the present example, mold 36 comes intomechanical contact with the imprinting material, spreading droplets 36,so as to generate a contiguous formation 50 of the imprinting materialover surface 44. In one embodiment, distance “d” is reduced to allowsub-portions 52 of imprinting layer 34 to ingress into and fillrecessions 38.

To facilitate filling of recessions 38, the imprinting material isprovided with the requisite properties to completely fill recessions 38while covering surface 44 with a contiguous formation of the imprintingmaterial. In the present embodiment, sub-portions 54 of imprinting layer34 in superimposition with protrusions 40 remain after the desired,usually minimum distance “d” has been reached. This action providesformation 50 with sub-portions 52 having a thickness t₁, andsub-portions 54, having a thickness t₂. Thicknesses “t₁” and “t₂” may beany thickness desired, dependent upon the application. Thereafter,formation 50 is solidified by exposing the same to the appropriatecuring agent, e.g., actinic radiation. This causes the imprintingmaterial to polymerize and cross-link. The entire process may occur atambient temperatures and pressures, or in an environmentally controlledchamber with desired temperatures and pressures. In this manner,formation 50 is solidified to provide side 56 thereof with a shapeconforming to a shape of a surface 58 of mold 36.

Referring to FIGS. 1, 2 and 3, the characteristics of the imprintingmaterial are important to efficiently pattern substrate 42 in light ofthe unique patterning process employed. For example, it is desired thatthe imprinting material have certain characteristics to facilitate rapidand even filling of the features of mold 36 so that all thicknesses t₁are substantially uniform and all thicknesses t₂ are substantiallyuniform. To that end, it is desirable that the viscosity of theimprinting material be established, based upon the deposition processemployed, to achieve the aforementioned characteristics. As mentionedabove, the imprinting material may be deposited on substrate 42employing various techniques. Were the imprinting material deposited asa plurality of discrete and spaced-apart droplets 46, it would bedesirable that the composition from which the imprinting material isformed have relatively low viscosity, e.g., in a range of 0.5 to 20centipoises (cPs). Considering that the imprinting material is spreadand patterned concurrently, with the pattern being subsequentlysolidified into formation 50 by exposure to radiation, it would bedesired to have the composition wet surface of substrate 42 and/or mold36 and to avoid subsequent pit or hole formation after polymerization.Were the imprinting material deposited employing spin coatingtechniques, it would be desired to use higher viscosity materials, e.g.having a viscosity greater than 10 cPs and typically, several hundred toseveral thousand cPs.

In addition to the aforementioned characteristics, referred to as liquidphase characteristics, it is desirable for the composition to providethe imprinting material with certain solidified phase characteristics.For example, after solidification of formation 50, it is desirable thatpreferential adhesion and release characteristics be demonstrated by theimprinting material. Specifically, it is beneficial for the compositionfrom which the imprinting material is fabricated to provide formation 50with preferential adhesion to substrate 42 and preferential release ofmold 36. In this fashion, reduced is the probability of distortion inthe recorded pattern resulting from the separation of mold 36 therefromdue to, inter alia, tearing, stretching or other structural degradationof formation 50.

The constituent components that form the imprinting material to providethe aforementioned characteristics may differ. This results fromsubstrate 42 being formed from a number of different materials. As aresult, the chemical composition of surface 44 varies dependent upon thematerial from which substrate 42 is formed. For example, substrate 42may be formed from silicon, plastics, gallium arsenide, mercurytelluride, and composites thereof. Additionally, substrate 42 mayinclude one or more layers, e.g., dielectric layer, metal layer,semiconductor layer, planarization layer and the like, upon whichformation 50 is generated. Additionally, mold 36 may be formed fromseveral materials, e.g., fused-silica, quartz, indium tin oxidediamond-like carbon, MoSi, sol-gels and the like.

It has been found that the imprinting material from which formation 50is generated may be fabricated from several different families of bulkmaterials. For example, the imprinting material may be fabricated fromvinyl ethers, methacrylates, epoxies, thiol-enes and acrylates, just toname a few.

Exemplary bulk materials for the imprinting material are as follows:

Vinyl Ether/BULK MATERIAL-A1 triethyleneglycol divinyl ethertris(4-vinyloxybutyl)trimellitate photoinitiator

A first vinyl ether component, triethyleneglycol divinyl ether, has thefollowing structure:

and comprises approximately 67.9% of the bulk material by weight. As aresult, the mechanical properties of formation 50 are primarilyattributable to triethyleneglycol divinyl ether. An exemplary source fortriethyleneglycol divinyl ether is the BASF Corporation of Mount Olive,N.J. available under the product name DVE-3.

A second vinyl ether component tris(4-vinyloxybutyl)trimellitate has thefollowing structure:

and comprises approximately 29.1% of the bulk material. The componenttris(4-vinyloxybutyl)trimellitate is available from Morflex Inc. ofGreensboro, N.C. under the tradename Vectomer 5015.

The photoinitiator component is a cationic photoinitiator that is amixture of triarylsulfonium hexafluoroantimonate salts in propylenecarbonate having the following structure:

the photoinitiator component comprises approximately 3% of the bulkmaterial and is available from the Dow Chemical Company of Midland,Mich. under the product name UVI 6976.

Vinyl Ether 2/BULK MATERIAL-A2 bis(4-vinyloxybutyl)adipate vinyl etherterminated polyester polymer photoinitiator

A first vinyl ether component, bis(4-vinyloxybutyl)adipate, has thefollowing structure:

and comprises approximately 19.4% of the bulk material by weight. Anexemplary source for bis(4-vinyloxybutyl)adipate is Morflex, Inc. ofGreensboro, N.C. under the product name Vectomer 4060.

The second vinyl ether component is a vinyl ether terminated polyesterpolymer that comprises approximately 77.6% of the bulk material byweight. As a result, the mechanical properties of formation 50 areprimarily attributable to the vinyl ether terminated polyester polymer.An exemplary source for the vinyl ether polyester polymer is Morflex,Inc. of Greensboro, N.C. under the product name Vectomer 1312. Thephotoinitiator comprises approximately 3% of the bulk material, byweight, and is that same as described above with respect to VINYL ETHERBULK MATERIAL 1: UVI 6976.

Methacrylate/BULK MATERIAL-A3 Organic Modified Silicate

An exemplary organic modified silicate ORMOSIL that may comprise 100% ofthe bulk material is Ormomer® b66 available from Micro Resist TechnologyGmbH, Berlin, Germany. The material is fabricated through a sol-gelprocess. Methacryl and epoxy functionality is attached to the material,with a photoinitiator component being incorporated for UV curing throughthe methacryl functionality.

Epoxy/BULK MATERIAL-A4 Diglycidyl Ether of Bisphenol A CationicPhotoinitiator

The diglycidyl ether of bisphenol A component has the followingstructure:

and comprises approximately 97% of the bulk material by weight. As aresult, the mechanical properties of formation 50 are primarilyattributable to the diglycidyl ether of bisphenol A component. Anexemplary source of diglycidyl ether of bisphenol A is Dow ChemicalCompany of Midland, Mich. under the product name DER 332. The cationicphotoinitiator component of the bulk material includes a mixture oftriarylsulfonium hexafluorophosphate salts in propylene carbonate,providing the following structure:

and comprises approximately 3% of the bulk material, by weight. Anexemplary source of the cationic photoinitiator is Dow Chemical Companyof Midland, Mich. under the product name UVI 6992.

Thiol-Ene/Bulk Material-A5 triethyleneglycol divinyl ether1,2-Bis(2-mercaptoethoxy)ethane triallyl isocyanurate ethyl2,4,6-trimethylbenzoylphenylphosphinate

The vinyl ether component comprises approximately 36.7% of the bulkmaterial by weight and has the structure discussed above with respect tothe product sold under the product name DVE-3. The1,2-Bis(2-mercaptoethoxy)ethane component has the following structure:

and comprises approximately 47.3% of the bulk material by weight. Anexemplary source of the 1,2-Bis(2-mercaptoethoxy)ethane component is theAldrich Chemical Company of Milwaukee, Wis. under the product name DMDO.As a result, the mechanical properties of formation 50 are primarilyattributable to the triethyleneglycol divinyl ether and1,2-Bis(2-mercaptoethoxy)ethane components.

The triallyl isocyanurate component has the following structure:

and comprises approximately 13% of the bulk material by weight. Anexemplary source of the triallyl isocyanurate component is the AldrichChemical Company of Milwaukee, Wis. under the product name TAIC.

The ethyl 2,4,6-trimethylbenzoylphenyl-phosphinate component comprisesapproximate 3% of the bulk material by weight and has the followingstructure:

An exemplary source of the ethyl 2,4,6-trimethylbenzoylphenylphosphinatecomponent is the BASF Corporation of Mount Olive, N.J. under the productname TPO-L.

Acrylate/Bulk Material-A6 isobornyl acrylate n-hexyl acrylate ethyleneglycol diacrylate 2-hydroxy-2-methyl-1-phenyl-propan-1-one

The acrylate component, isobornyl acrylate (IBOA), has the followingstructure:

and comprises approximately 55% of bulk material by weight, but may bepresent in a range of 20% to 80%, inclusive. As a result, the mechanicalproperties of formation 50 are primarily attributable to IBOA. Anexemplary source for IBOA is Sartomer Company, Inc. of Exton, Pa.available under the product name SR 506.

The component n-hexyl acrylate (n-HA) has the following structure:

and comprises approximately 27% of bulk material by weight, but may bepresent in a range of 0% to 50%, inclusive. Also providing flexibilityto formation 50, n-HA is employed to reduce the viscosity of the priorart bulk material so that bulk material, in the liquid phase, has aviscosity in a range 2-9 Centipoises, inclusive. An exemplary source forthe n-HA component is the Aldrich Chemical Company of Milwaukee, Wis.

A cross-linking component, ethylene glycol diacrylate, has the followingstructure:

and comprises approximately 15% of bulk material by weight, and may bepresent in a range of 10% to 50%, inclusive. EGDA also contributes tothe modulus and stiffness buildup, as well as facilitates cross-linkingof n-HA and IBOA during polymerization of the bulk material.

An initiator component, 2-hydroxy-2-methyl-1-phenyl-propan-1-one isavailable from Ciba Specialty Chemicals of Tarrytown, N.Y. under thetrade name DAROCUR® 1173, and has the following structure:

and comprises approximately 3% of the bulk material by weight, and maybe present in a range of 1% to 5%, inclusive. The initiator isresponsive to a broad band of ultra-violet radiation generated by amedium-pressure mercury lamp. In this manner, the initiator facilitatescross-linking and polymerization of the components of the bulk material.

Acrylate/BULK MATERIAL-A7 isobornyl acrylate n-hexyl acrylate ethyleneglycol diacrylate 2-hydroxy-2-methyl-1-phenyl-propan-1-one

As can be seen, BULK MATERIAL-A7 is identical to BULK MATERIAL-A6 interms of the identity of the constituent components. The two materialsdiffer in terms of the percentage of each of the constituent componentspresent. In BULK MATERIAL-A7, IBOA comprises approximate 47% of thematerial by weight and n-HA and EGDA each comprises 25% of the bulkmaterial by weight. DAROCUR® 1173,2-hydroxy-2-methyl-1-phenyl-propan-1-one component comprisesapproximately 3% of the material by weight.

Acrylate/BULK MATERIAL-A8 genomer 1122 isobornyl acrylate 1,6-HexanediolDiacrylate 2-hydroxy-2-methyl-1-phenyl-propan-1-one

The first acrylate component, genomer 1122 is an aliphatic urethaneacrylate available from Rahn USA Corporation of Aurora, Ill. and has thefollowing structure:

and comprises approximately 21% of the bulk material by weight, but maybe present in a range of 0 to 50%. The acrylate component isobornylacrylate (IBOA) is as described above and comprises approximately 56% byweight of the composition, but may be present in a range of 20 to 80%.The acrylate component 1,6-hexanediol diacrylate is available from UCBChemicals, Smyna, Ga. and has the following structure:

and comprises approximately 20% of bulk material by weight, but may bepresent in a range of 10% to 50%, inclusive. The initiator component,2-hydroxy-2-methyl-1-phenyl-propan-1-one is as described above andcomprises approximately 3% of the composition by weight. To provideimproved wetting characteristics of BULK MATERIAL A8, additionalfluorinated acrylates, such as 1H,1H-perfluoro-n-decyl acrylate may beincluded to lower the contact angle of the same. This fluorinatedacrylate is available from Exfluor Research Corporation, Round Rock,Tex. under the tradename C10ACRY. One advantage with bulk material A-8is that it has a viscosity of approximately 11 cPs which makes the samesuitable for both drop-dispense and spin-coating techniques.

It was discovered, however, that desirable preferential adhesion andrelease properties, as discussed above, may be achieved by producing aweak boundary layer, lamella 60, between mold 36, surface 58 andformation 50. Lamella 60 remains after solidification of the imprintingmaterial. As a result, the adhesion forced between mold 36 and formation50 is minimal. To that end, found beneficial was employing a compositionfor the imprinting material that includes one of the bulk materialsdiscussed above along with a component that contains low surface energygroups, referred to herein as a surfactant component. After depositionof the imprinting material, the surfactant component rises, after aperiod of time, to the air liquid interface, providing droplets 146 ofimprinting material with a bifurcated concentration of materials.

In a first portion, droplets 146 include a higher concentration of thesurfactant component, referred to as a surfactant-component-rich (SCR)sub-portion 136, than the second portion, referred to as asurfactant-component-depleted (SCD) sub-portion 137. SCD sub-portion 137is positioned between surface 44 and SCR sub-portion 136. SCRsub-portion 136 attenuates the adhesion forces between mold 36 and theimprinting material, once solidified. Specifically, the surfactantcomponent has opposed ends. When the imprinting material is in theliquid phase, i.e., polymerizable, one of the opposed ends has anaffinity for the bulk material included in the imprinting material. Theremaining end has a fluorine component. As a result of the affinity forthe bulk material, the surfactant component is orientated so that thefluorine component extends from an air-liquid interface defined by theimprinting material and the surrounding ambient. Upon solidification ofthe imprinting material, a first portion of the imprinting materialgenerates a lamella 60 and a second portion of the imprinting materialis solidified, i.e., polymeric material shown as formation 50. Lamella60 is positioned between formation 50 and mold 36. Lamella 60 resultsfrom the presence and location of the fluorine components in the SCRsub-portion 136. Lamella 60 prevents strong adhesion forces from beingdeveloped between mold 36 and formation 50. Specifically, formation 50has first and second opposed sides 62 and 64. Side 62 adheres tosubstrate 42 with a first adhesion force. Side 64 adheres to mold 36with a second adhesion force. Lamella 60 results in the second adhesionforce being less than the first adhesion force. As a result, mold 36 maybe easily removed from formation 50 while minimizing distortions and/orthe force required to separate mold 36 therefrom. Although formation 50is shown with side 62 being patterned, it should be understood that side62 may be smooth, if not planar. Furthermore, if desired, it is possibleto generate lamella 60 so as to be disposed between formation 50 andsubstrate 42. This may be achieved, for example, by applying imprintingmaterial to mold 36 and subsequently contacting substrate with theimprinting material. In this manner, it can be said that formation 50,i.e., polymeric material, will be disposed between lamella 60 and thebody, mold 36 or substrate 42, upon which the polymerizable material isdeposited.

It should be understood that were the imprinting material depositedemploying spin-coating techniques, similar bifurcated concentration ofmaterials occurs, as shown in FIG. 5 with respect to SCR sub-portion 236and second and SCD sub-portion 237. The time required for thebifurcation is dependent upon several factors, including the size ofmolecules in the imprinting material and the viscosity of the imprintingmaterial. Only a few seconds is needed to achieve the aforementionedbifurcation of imprinting material with viscosity below twenty cPs.Imprinting material with viscosity in the hundreds of cPs, however, mayrequire a few seconds to several minutes.

Various surfactant components, or combinations of surfactant components,can be included in the bulk materials to form lamella 60. These includenonionic fluorinated surfactant components having the following generalformula:

F(CF₂CF₂)_(X)CH₂CH₂O(RO)_(Y)R′

where (RO)_(Y) is a poly(oxyalkylene) group, that includes groups havingtwo to four carbon atoms such as —CH₂CH₂—, —CH₂CH₂CH₂—, —CH(CH₃)CH₂—, or—CH(CH₃)CH(CH₃)—, and R′ is a terminal group of H or C₁ to C₄ alkyl,preferably H or methyl and X and Y are integers.

Another example of nonionic fluorinated surfactant components has thefollowing general formula:

where R and R′ can be either H or methyl; R and R′ can be identical ordiffer. R″ is a linking group that may be omitted or a sulfonyl groupsuch as —SO₂N(R′″″)—. with R′′″ being C₁ to C₆ alkyl and typically C₁ toC₄ alkyl. The component (OR′″)_(z) is a poly(oxyalkylene) group,typically including groups having 2 to 4 carbon atoms such as —CH₂CH₂—,—CH₂CH₂CH₂—, —CH(CH₃)CH₂—, or —CH(CH₃)CH(CH₃)—. R″″ is a terminal groupof methyl, H or C₁ to C₄ alkyl and typically H or methyl. The ratio of xto y is in a range of 1:2 to 3:1 and more preferably in a range of 1:1to 2:1.

It should be understood that the oxyalkylene groups in thepoly(oxyalkylene) group may be the same, as in poly(oxyethylene), or twoor more of differing oxyalkylene units may be irregularly distributed inthe poly(oxyalkylene) group. More specifically, the poly(oxyalkylene)group may be made up of straight or branched chain oxypropylene unitsalone or oxyethylene units alone, or straight or branched oxypropyleneunits and oxyethylene units may be present in alternate blocks. In thecase of alternate blocks of oxyethylene and oxypropylene, the ratio theoxyethylene to oxypropylene is in a range of 2.0-0.5 to 1. Also,unattached blocks of poly(oxyalkylene) may be present in the polymermatrix. Chain transfer agents such as octyl mercaptan may be alsopresent.

Exemplary nonionic fluorinated surfactant components that may beemployed are fluoro-aliphatic polymeric esters, fluorosurfactants of thepolyoxyethylene or polyalkyl ether type, or fluoroalkyl polyethers asset forth in U.S. Pat. Nos. 3,403,122, 3,787,351, 4,803,145, 4,835,084,4,845,008, 5,380,644, 5,747,234, and 6,664,354 which are incorporatedherein by reference. Suitable commercially available examples of thesurfactant components included are sold by Dupont under product namesZONYL® FSO, ZONYL® FSO-100, ZONYL® FSN-100, ZONYL® FS-300; sold by 3MCompany under the product names FC-4432, FC-4430, FC430; sold by MasonChemical Company of Arlington Heights, Ill. under the product namesMASURF® FS425, MASURF® FS1700, MASURF® FS-2000, MASURF® FS-1230; sold byCiba-Geigy Corp under the product names Lodyne S-107B, Lodyne S-220N,Lodyne S-222N; sold by Daikin of Japan under the product names UnidyneNS1602, Unidyne NS1603, Unidyne NS1606; and sold by Dainippon Ink &Chemical under the product name MegaFace R-08. In addition to, or inlieu of the nonionic fluorinated surfactant components, ionicfluorinated surfactant components may be employed in the compositionfrom which the imprinting material is formed, along with the bulkmaterials discussed above.

In lieu of, or in addition to, the non-ionic fluorinated surfactantcomponents, the ionic type of fluorinated surfactant components can workas well. An exemplary ionic surfactant is an anionic phosphatefluorosurfactant sold by DuPont of Wilmington, Del. under the tradenameZONYL® UR, which has the following formula:

wherein, x=1 or 2, y=2 or 1, x+y=3, z=0 to about 6. In addition toZONYL® UR, other anionic surfactant components based upon fluorinatedphosphoric, polyphosphoric acid ester, sulfonic acid ester, alkylsurface and carboxylic acid ester types may be employed.

In lieu of, or in addition to, the non-ionic and anionic surfactantcomponents, a zwitterionic surfactant may be employed with the bulkmaterials discussed above for the composition from which the imprintingmaterial is fabricated. An exemplary zwitterionic surfactant has thefollowing general formula:

A commercially available zwitterionic surfactant is a fluoroaliphaticamine oxide available from the Mason Chemical Company under thetradename MASURF® FS230. Cationic surfactant components may be employed,as well, such as fluorinated surfactant components like quaternaryammonium salts available from DuPont under the trade name ZONYL® FSDwhich has the following formula:

F(CF₂CF₂)_(X)-alkyl-N⁺R₃CL⁻

where x is an integer in a range of 1 to 7, inclusive. Additionally asurfactant containing both fluorine and silicon atoms can work, as well.An exemplary surfactant containing silicon is MEGAFACE® R-08 mentionedabove.

Although the foregoing has been discussed with respect to havingfluorine-containing surfactant components, it is possible to employnon-fluorine-containing surfactant components. This is particularlyuseful when a mixture of surfactant components is employed, wherein oneof the surfactant components is fluorine-containing with the remainingsurfactant components of the mixture of surfactant components being anon-fluorine-containing surfactant and/or a fluorine-containingsurfactant. An exemplary mixture of surfactant components may includeone or more of the fluorine-containing surfactant components describedabove. The remaining surfactant components may be one or more of asiloxane-based-surfactant and/or a hydrocarbon-based-surfactant.Examples of siloxane-based surfactant components are available from DowCorning of Midland, Mich. under the trade names Q2-5211 and SYLGARD®309, both of which are trisiloxane-type surfactant components. Siloxanepolyether types may be employed, as well.

Hydrocarbon surfactant components suitable for use in the presentinvention include any that facilitate providing a composition with low“dynamic” surface tension and/or increasing the solubility of thefluorinated surfactant into the bulk materials. Exemplary hydrocarbonsurfactant components are available from BASF of Ontario, Canada underthe tradename TETRONIC®, e.g., TETRONIC® 701, which are believed to betetrafunctional block copolymers of propylene oxide, ethylene oxide, andethylene diamine. Other hydrocarbon surfactant components are availablefrom Dow Chemical Company of Midland, Mich. under the trade namesTERGITOL® and TRITON®, e.g., TERGITOL® NP-10, TRITON® X-100 and TRITON®X-45. The TERGITOL® surfactant components are alkyl polyethylene oxides,and the TRITON® surfactant components are alkyl phenyl polyethyleneoxides. Uniqema Americas of New Castle, Del. also provides suitablehydrocarbon surfactant components containing polyethoxylated alcoholsand esters under the tradename BRIJ®, e.g., BRIJ® 30. Acetylenicpolyethlene oxide-containing hydrocarbon surfactant components areavailable from Air Products and Chemicals, Inc. of Allentown, Pa. underthe trade names SULFYNOL® and DYNOL®, e.g., SULFYNOL® 104, SULFYNOL®440, SULFYNOL® 2502, and DYNOL® 604.

Typically, the composition formed employing the bulk materials mentionedabove includes a quantity of surfactant components, or mixture ofsurfactant components, that is in a range of 0.05% to 5% of thecomposition by weight, and more particularly 0.25% to 2% by weight. Theremaining portion of the composition comprises one or more of the bulkmaterials, described above. Typically the composition from which theimprinting material is fabricated is applied employing drop-dispensetechniques at room temperatures and in the presence of a helium-purgedenvironment, e.g., a helium-saturated atmosphere. The drop-dispensetechnique is employed for compositions having viscosities in a range of1-20 cPs at room temperature. For higher viscosity compositions, e.g.,in a range of 10-500,000 cPs, but more particularly, compositions from10-20,000 cPs, at room temperature, spin-coating techniques may beemployed.

To demonstrate the improved preferential adhesion and preferentialrelease provided by the presence of the surfactant components describedabove in imprinting material, several compositions including the bulkmaterials and surfactant components described above were tested.Specifically, the following surfactant components were employed:

S1 FC-4430

As mentioned above, the surfactant FC-4430 is available from the 3MCompany of St. Paul, Minn. as the NOVEC® Fluorosurfactant FC-4430. TheNOVEC® FC-4430 fluorosurfactant is a non-ionic acrylic copolymer basedfluorochemical surfactant containing perfluorobutane sulfonate (PFBS)segments.

S2 FS-1230

The surfactant FS-1230 is believed to originate from Asahi Glass, inJapan and distributed in the United States of America by Mason Chemicalof Arlington Heights, Ill. under the product name MASURF® FS-1230 andhas the following general formula:

F₃CF₂C—(CF₂CF₂)_(x)CH₂CH₂—O(CH₂CH₂O)_(y)H

where X and Y are integers. MASURF® FS-1230 is a 30% activefluoroaliphatic polyoxyethylene fluorosurfactant in a water/isopropanolsolution. In the experiments that resulted in the data recited below,the water and isopropanol were removed before the surfactant wasincorporated into the composition for the imprinting material.

S3 FSO-100

The surfactant FSO-100 is an ethoxylated nonionic fluorosurfactant thathas the following structure:

where x is an integer in a range of 0 to 6, inclusive; and y is aninteger in a range of 0 to 15, inclusive.

S4 FC-4432

As mentioned above, the surfactant FC-4432 is available from the 3MCompany of St. Paul, Minn. as the NOVEC® Fluorosurfactant FC-4432. It isa non-ionic polymeric fluorochemical surfactant. The NOVEC® FC-4432fluorosurfactant is based on perfluorobutane sulfonate (PFBS) chemistry.

S5 F021004

The component F021004 is a surfactant-like component that is availablefrom Fluorous Technologies, Inc. of Pittsburgh, Pa. The chemical name isDiisopropyl(1H,1H,2H,2H-perfluorododecyl)silane. The surfactant-likecomponent F021004 has the following structure:

S6 ZONYL® UR

The surfactant ZONYL® UR is an anionic phosphate fluorosurfactantavailable from Dupont of Wilmington, Del. that has the followingstructure:

where x is an integer having a value of 1 or 2; y is an integer having avalue of 2 or 1; Z is an integer having a value in a range of 0 to 6,inclusive, where x+y=3.

S7 Combination of FSO-100 and R-08

The surfactant R-08 is a nonionic fluorinated acrylic copolymer basedsurfactant. As mentioned above, the surfactant R-08 is available fromDainippon Ink & Chemical of Japan under the product name is MEGAFACE®R-08. The combination surfactant S7 is 50% FSO-100 and 50% R-08.

S8 Combination of FSO-100 SURF YNOL® 104

The surfactant SURF YNOL® 104 is an acetylenic hydrocarbon-basedsurfactant having the chemical name2,4,7,9-tetramethyl-5-decyne-4,7-diol. The surfactant SURF YNOL® isavailable from Air Products and Chemicals, Inc. of Allentown, Pa. andhas the following structure:

The combination surfactant S8 is 50% FSO-100 and 50% SURF YNOL® 104.

The surfactant components and bulk materials described above wereemployed to formulate additional compositions to generate comparativedata of the preferential adhesion and preferential release propertieswith respect to the twelve compositions and the eight bulk materials,discussed above. The compositions and/or bulk materials were depositedand then solidified between two glass slides. Each glass slide wasapproximately 1 mm thick, 75×25 mm in the lateral dimension. Droplets offluidic imprinting material were disposed on a glass slide; the secondslide was laid in a cross direction pattern. The imprinting material wassubsequently cured. A four-point bending compression force was appliedto separate the slides. To that end, a four-point bending fixture (notshown) was adopted for the adhesion test and technique, similar to thatdescribed in “Measurement of Adhesive Force Between Mold andPhotocurable Resin in Imprint Technology” Japanese Journal of AppliedPhysics, Vol. 41 (2002) pp. 4194-4197. The maximum force/load was takenas the adhesion value. The beam distance of the top and bottom twopoints is 60 mm. The load was applied at the speed of 0.5 mm per minute.The compositions and test results are shown in FIG. 8.

As seen in FIG. 8 for composition A1, only 3.4 pounds of separationforce is required to separate superimposed glass-slides (not shown)having a cured imprinting material disposed therebetween formed from acomposition bulk material A1 and surfactant S2, shown as A1-S2. This ismuch less than the 7.5 pounds of separation force required to separatecured imprinting material formed from a composition of about 99.5% bulkmaterial A1 and about 0.5% surfactant S1, shown as A1-S1. More tellingis the 61% reduction in the separation force realized when compared tothe separation force required to separate superimposed glass slides (notshown) having a cured bulk material A1, disposed therebetween, nothaving a surfactant included therein, shown as A1-NS. The A1-NS, A1-S1and A1-S2 compositions each have a room temperature viscosity ofapproximately 8cPs and deposited at room temperature employingdrop-dispense techniques. The A1-S2 composition consisted ofapproximately 99.5% of bulk material A1 and 0.5% of surfactant S2. TheA1-S1 composition consisted of approximately 99.5% of bulk material A1and 0.5% of surfactant S1.

As seen in FIG. 9 from the separation data concerning bulk material A2,1.7 pounds of separation force was required to separate superimposedglass-slides (not shown) having cured imprinting material. A compositioncontaining bulk material A2 and surfactant S3, shown as A2-S3 wasemployed to form the cured imprinting material. This separation forcerequired is much less than the 2.6 pounds of separation force requiredin the presence of cured imprinting material formed from a compositionof bulk material A2 and surfactant S4, shown as A2-S4. More telling isthe 50% reduction in the separation force realized when compared to theseparation force required to separate superimposed glass slides (notshown) having a cured bulk material A2, disposed therebetween, in theabsence of a surfactant, shown as A2-NS. The A2-NS, A2-S3 and A2-S4compositions each has a room temperature viscosity of approximately300cPs and deposited at room temperature employing spin-on techniques.The A2-S3 composition consisted of approximately 99.5% of bulk materialA2 and 0.5% of surfactant S3. The A2-S4 composition consisted ofapproximately 99.5% of bulk material A2 and 0.5% of surfactant S4.

As seen in FIG. 10 from the separation data concerning bulk material A3,only 2.0 pounds of separation force was required to separatesuperimposed glass-slides (not shown) having a cured imprinting materialdisposed therebetween. The cured imprinting material was formed from acomposition containing bulk material A3 and surfactant S4, shown asA3-S4. This is much less than the 3.0 pounds of separation forcerequired in the presence of cured imprinting material formed fromcomposition of bulk material A3 and surfactant S1, shown as A3-S1. Theseparation force associated with A3-S4 is also less than the separationforce required in the presence of cured imprinting material formed froma composition of bulk material A3 and surfactant S3, shown as A3-S3.More telling is the 72% reduction in the separation force realized whencompared to the separation force required to separate superimposed glassslides (not shown) having a cured bulk material A3, disposedtherebetween, in the absence of a surfactant, shown as A3-NS. The A3-NS,A3-S1, A3-S3 and A3-S4 compositions each has a room temperatureviscosity in a range of approximately 10,000 to 12,000 cPs, inclusive,and deposited at room temperature employing spin-on techniques. TheA3-S1 composition consisted of approximately 99.5% of bulk material A3and 0.5% of surfactant S1. The A3-S3 composition consisted ofapproximately 99.5% of bulk material A3 and 0.5% of surfactant S3. TheA3-S4 composition consisted of approximately 99.5% of bulk material A3and 0.5% of surfactant S4.

As seen in FIG. 11 from the separation data concerning bulk material A4,the reduction of forces required for separating the superimposedglass-slides (not shown) having a cured composition disposedtherebetween containing bulk material A4 and surfactant S4, shown asA4-S4, required only 5.0 pounds. This is less than the 5.4 pounds ofseparation force required for a composition of bulk material A4 andsurfactant S3, shown as A4-S3. More telling is the 40% reduction in theseparation force realized when compared to the separation force requiredto separate superimposed glass slides (not shown) having a cured bulkmaterial A4, disposed therebetween, in the absence of a surfactant,shown as A4-NS. The A4-NS, A4-S3 and A4-S4 compositions each has a roomtemperature viscosity approximately 5,000cPs and deposited at roomtemperature employing spin-on techniques. The A4-S1 compositionconsisted of approximately 99.5% of bulk material A4 and 0.5% ofsurfactant S1. The A4-S3 composition consisted of approximately 99.5% ofbulk material A4 and 0.5% of surfactant S3. The A4-S4 compositionconsisted of approximately 99.5% of bulk material A4 and 0.5% ofsurfactant S4.

As seen in FIG. 12 from the separation data concerning bulk material A5,only 0.62 pounds of separation force is required for separating thesuperimposed glass-slides (not shown) having a cured imprinting materialdisposed therebetween. The cured imprinting material was formed from acomposition of bulk material A5 and surfactant S3, shown as A5-S3. Thisis less than the separation force required for cured imprinting materialformed from a composition of either bulk material A5 and surfactant S1,shown as A5-S1 or bulk material A5 and surfactant S4, shown as A5-S4.More telling is the 72% reduction in the separation force realized whencompared to the separation force required to separate superimposed glassslides (not shown) having a cured bulk material A5, disposedtherebetween, in the absence of a surfactant, shown as A5-NS. The A5-NS,A5-S1, A5-S3 and A5-S4 compositions each has a room temperatureviscosity in a range of approximately 20 to 30 cPs, inclusive, anddeposited at room temperature employing spin-on techniques. The A5-S1composition consisted of approximately 99.5% of bulk material A5 and0.5% of surfactant S1. The A5-S3 composition consisted of approximately99.5% of bulk material A5 and 0.5% of surfactant S3. The A5-S4composition consisted of approximately 99.5% of bulk material A5 and0.5% of surfactant S4.

The separation force data concerning bulk material A6 in the absence ofa surfactant being cured between two superimposed transfer layers isshown in FIG. 13 as A6-NS B/B. Specifically, each of two superimposedglass slides (not shown) has a layer of DUV30J formed thereon. DUV30J isavailable from Brewer Science, Inc. of Rolla, Mo. It is desired that thecured bulk material A6 adheres well to the transfer layer (not shown)and easily releases from the surface of an imprint template (not shown).Also shown is the separation force data concerning bulk material A6 inthe absence of a surfactant with respect to being cured between twosuperimposed glass slides (not shown) having no previous layer thereon,shown as A6-NS.

As seen for the separation data concerning bulk material A6, theseparation force required for separating the superimposed glass-slides(not shown), without the aforementioned transfer layer being present andhaving a cured composition disposed therebetween containing bulkmaterial A6 and surfactant S3, shown as A6-S3, required only 0.95pounds. This is less than the pounds of separation force required for acomposition of bulk material A6 and surfactant S5, shown as A6-S5 or theseparation forces required for A6-NS B/B. More telling is the 84%reduction in the separation force realized when compared to theseparation force required to separate superimposed glass slides (notshown) having a cured bulk material A6-NS.

The data suggests that selective adhesion has been achieved. Although S3and S5 have perfluoro-hydrophobic groups, S3 appears to be much moreefficient in reducing the adhesion than S5. It is believed, therefore,that structure variations of the fluorinated additives will havesignificant impacts on the release performance. For example, S3 has asurfactant molecule that contains both a hydrophobic tail and ahydrophilic head, which as shown provides desirable releasecharacteristics. The A6-NS, A6-S3 and A6-S5 compositions have a roomtemperature viscosity of approximately 4cPs and deposited at roomtemperature employing drop-dispense techniques. The A6-S3 compositionconsisted of approximately 99.5% of bulk material A6 and 0.5% ofsurfactant S3. The A6-S5 composition consisted of approximately 99.5% ofbulk material A6 and 0.5% of surfactant S5.

The separation force data concerning bulk material A7 in the absence ofa surfactant being cured between two superimposed transfer layers isshown in FIG. 14 as A7-NS B/B. Specifically, each of two superimposedglass slides (not shown) has a layer of DUV30J formed thereon, asdiscussed above. Also shown is the separation force data concerning bulkmaterial A7 in the absence of a surfactant with respect to being curedbetween two superimposed glass slides (not shown) having no previouslayer thereon, shown as A7-NS. As is expected from a review of theprevious data, the presence of surfactant components provides greatlyimproved release properties for compositions imprinting materialincluding bulk material A7. Also demonstrated is the success ofcombination surfactant components, such as S7 and S8, in reducing theseparation force required. The A7-NS, A7-S1, A7-S3, A7-S4, A7-S5, A7-S6,A7-S7 and A7-S8 compositions each has a room temperature viscosity ofapproximately 4 cPs and deposited at room temperature employingdrop-dispense techniques. The A7-S1 composition consisted ofapproximately 99.5% of bulk material A7 and 0.5% of surfactant S1. TheA7-S3 composition consisted of approximately 99.5% of bulk material A7and 0.5% of surfactant S3. The A7-S4 composition consisted ofapproximately 99.5% of bulk material A7 and 0.5% of surfactant S4. TheA7-S5 composition consisted of approximately 99.5% of bulk material A7and 0.5% of surfactant S5. The A7-S6 composition consisted ofapproximately 99.5% of bulk material A7 and 0.5% of surfactant S6. TheA7-S7 composition consisted of approximately 99.5% of bulk material A7and 0.5% of surfactant S7. The A7-S8 composition consisted ofapproximately 99.5% of bulk material A7 and 0.5% of surfactant S8.

Referring to FIG. 2, one consideration with providing surfactants isthat introduction of the same into imprinting material may increase thetime required to fill the features of mold 36. As mentioned above, layer70 is formed on surface 58 that results from contact with the imprintingmaterial. The release properties provided by the surfactants result fromthe hydrophobicity of the same, which conflict with the wettingcharacteristics that are desired to rapidly cover the features of mold36. Specifically, it is believed that, in the case of surfactants thatinclude fluorine-atoms within a molecule, too great a quantity of thefluorine atoms within a molecule and coupling with too great a quantityof the fluorine-containing molecules results in the generation ofclusters of fluorine-containing molecules. These clusters, especiallywith CF₃ end groups extending from the air-liquid interface, is believedto provide layer 70 with an undesirable hydrophobicity profile that maysubstantially affect the wetting characteristics of the imprintingmaterial with respect to surface 58.

It is believed that by appropriately distributing the fluorine atomswithin a surfactant molecule, as well as the distribution of thefluorine-containing molecules throughout the volume of layer 70, andtherefore, referred to collectively as the distribution of the fluorineatoms throughout the volume, an acceptable hydrophobicity profile may beachieved. Upon achieving the desired distribution of fluorine atomswithin a surfactant molecule and fluorine-containing molecules in layer70, lamella layer 60 is provided with an optimum fluorine density toprovide the desired preferential release and adhesion, without undulylimiting the wettability of surface 58 by the imprinting material. As aresult satisfactory fill and release properties are provided to theimprint process. This typically occurs upon lamella layer 60 having athickness of approximately 1 nm.

One manner, in which to determine that the desired distribution offluorine atoms within a surfactant molecule and fluorine-containingmolecules are present involves measuring the contact angle of theimprinting material in contact with surface 58. To that end, agoniometer is used for contact angle measurement. Molds 56 formed fromfused silica were cleaned in a piranha solution and stored in a nitrogenpurged environment. The piranha solution consisted of a mixture of 2parts concentrated H₂SO₄ and 1 part H₂O₂ mixed at room temperature. Mold36 is then rinsed with a surfactant component Isopropyl Alcohol (IPA)mixture, e.g., the IPA mixture contained 0.01% of the surfactantcomponent with the remainder consisting essential of IPA. After therinse, mold 36 was subjected to a stream of nitrogen fluid, e.g.,nitrogen gas, to blow-dry the same. Once again, mold 36 was exposed tothe same IPA mixture and then dried by exposure to the nitrogen fluidstream. Droplets of imprinting material were then deposited upon mold 36in volumes of in a range of 2 μl to 5 μl, approximately. Measured is thecontact angle of several different droplets located at various locationsover surface 58. In the present example contact angle measurements aremade corresponding to 7 different locations on mold 36, using thegoniometer. An average value of the seven contact angle measurements aremade to obtain the final contact angle values. Considering that layer 70is replenished each time the same contacts imprinting material onsubstrate, the foregoing experiment is believed to be an accuratedetermination of the relative wetting properties of differing imprintingmaterial compositions.

The contact angle, surfactant treatment solution, and fillingperformance are shown below

Wettability Characteristics for Bulk Material A7-1 FC-4430 & FC-4430 &R-08 & Surfactant FSO-100 FC-4432 R-08 R-08 FS-1230 Contact 43.2° 20.2°13.8° 17.3° 22.7° AngleBulk material A7-1 is identical to BULK MATERIAL-A7 in terms of theidentity of the constituent components, excepting the addition of asurfactant component. The two materials differ in terms of thepercentage of each of the constituent components present. In BulkMaterial A7-1, approximately 46.875% of the composition by weight isIBOA, 24.875% of the composition by weight is nHA, 24.875% of thecomposition by weight is EGDA, 2.875% of the composition by weight isDarocur 1173; and approximately 0.5% of the composition being asurfactant component. Specifically, with 0.5% of the Bulk Material A7-1consisting of the surfactant FSO-100, the least desirable wettabilitycharacteristics are provided. The contact angle is the greatest at43.20. Compare the contact angle of 13.80 provided upon Bulk MaterialA7-1 consisting of 0.5% of the combination surfactant R-08 and FC-4430,wherein R-08 and FC-4430 each comprises 0.25% of Bulk Material A7-1. Asa result, the time required to fill the features of mold 36 is less forlayer 70 including combination surfactant R-08 and FC-4430 than forlayer 70 including FSO-100. For the remaining measurements, a contactangle of approximately 20.20 when the combination surfactant FC-4430 andFC-4432 included in the Bulk Material A7-1 wherein FC-4430 comprisesapproximately 0.333% of the composition by weight and FC-4432 comprisesapproximately 0.167% of the composition by weight. Another surfactantcombination consisting of R-08 and FS-1230 presented a contact angle ofapproximately 22.70, in which R-08 comprised of approximately 0.4% byweight of Bulk Material A7-1, by weight, and FS-1230 comprised ofapproximately 0.1% of Bulk Material A7-1, by weight.

Wettability Characteristics for Bulk Material A8-1 FSO- FC- ES-Surfactant 100 4432 FC-4430 2000 R-08 S-222N Contact 49.7° 26.5° 17.2°21.4° 18.2° 19.2° AngleBulk material A8-1 is identical to BULK MATERIAL-A8 in terms of theidentity of the constituent components, excepting the addition of asurfactant component. The two materials differ in terms of thepercentage of each of the constituent components present. In BulkMaterial A8-1, approximately 20.875% of the composition by weight is theacrylate component Genomer 1122 and 55.875% of the composition by weightis IBOA. The acrylate component HDODA is approximately 19.875% byweight, and Darocur 1173 is approximately 2.875% of the composition byweight. The remaining 0.5% of the composition is a surfactant component.Specifically, with 0.5% of the Bulk Material A8-1 consisting of FSO-100,the least desirable wettability characteristics are provided. Thecontact angle is the greatest at 49.70. Compare the contact angle of17.2% provided upon Bulk Material A8-1 consisting of 0.5% of thesurfactant FC-4430. As a result, the time required to fill the featuresof mold 36 is less for layer 70 including surfactant FC-4430 than forlayer 70 including FSO-100. For the remaining measurements, a contactangle of approximately 18.20 was presented when the R-08 surfactant isincluded in Bulk Material A8-1. With surfactant S-222N included in BulkMaterial A8-1 a contact angle of 19.2° is presented, and a contact angleof 21.40 is presented when the surfactant FS-2000 is included in BulkMaterial A8-1. A contact angle of 26.50 is presented when surfactantFC-4432 is included in Bulk Material A8-1.

It should be understood that similar benefits of preferential adhesionand release with desirable wettability characteristics may be achievedby varying the surfactant composition on mold 36 or in the bulk materialor both. For example, increasing the surfactant concentration in bulkmaterial A8-1 to 0.7% of the composition by weight with 0.2% comprisingTergitol NP-10 and 0.5% being FS-2000 presented the second best wettingcharacteristics evidenced by a contact angle of approximately 17.4%. Itshould be noted that for this measurement, about 0.012% of the IPAmixture, mentioned above, consisted of the surfactant mixture FS-2000and Tergitol NP-10, instead of 0.01% of the solution. In this example, asurfactant mixture is employed in which fluorine-containing andnon-fluorine-containing surfactants are employed. Tergitol NP-10 is ahydrocarbon surfactant that has a faster dynamic speed than fluorinatedsurfactants, such as FS-2000.

Additionally, the surfactant composition may be modified by employing adiffering surfactant in layer 70 than is included in the imprintingmaterial that is contacted by the mold. For example,

Bulk Material A7-2 FC-4430 R-08 FC- & & Surfactant 4430 FC-4432 FC-4430R-08 FC-4432 FC-4430 Contact 43.2° 26° 18.1° 20.0° 22° 14.7° Angle

Bulk material A7-2 includes all of the constituent components ofmaterial A7-1 and includes a surfactant FSO-100. In Bulk Material A7-2,approximately 46.875% of the composition by weight is IBOA, 24.875% ofthe composition by weight is nHA, 24.875% of the composition by weightis EGDA, 2.875% of the composition by weight is Darocur 1173; andapproximately 0.5% of which is FSO-100. Specifically, surface 58 coatedwith the IPA mixture including FSO-100, the least desirable wettabilitycharacteristics are provided, with the contact angle being the greatestat 43.20. With surface 58 coated with the combination surfactant R-08and FC-4430, each of which comprises 0.5% of the IPA mixture, thatcontact angle presented is 14.7%. For the remaining measurements, acontact angle of approximately 18.10 is presented when surface 58 iscoated with the FC-4430 surfactant, and a contact angle of approximately200 is present when surface 58 is coated with the R-08 surfactant. Whensurface 58 is coated with a combination surfactant including FC-4430 andFC-4432 and is deposited in layer 70, a contact angle of approximately220 is presented. FC-4430 comprises 0.333% of the IPA mixture andFC-4432 comprises 0.167% of the IPA mixture, by weight. When surface 58is coated with FC-4432, absent any other surfactant, a contact angle ofapproximately 26.00 is presented. As can be seen, therefore, by properlyselecting the surfactant component in each of the bulk materials, thedesired wetting characteristics may be obtained, along with the desiredpreferential adhesion and release characteristics.

The embodiments of the present invention described above are exemplary.Many changes and modifications may be made to the disclosure recitedabove, while remaining within the scope of the invention. The scope ofthe invention should, therefore, be determined not with reference to theabove description, but instead should be determined with reference tothe appended claims along with their full scope of equivalents.

1. An imprint lithography mold assembly, comprising: (a) a mold having asurface; (b) a substrate having a surface; and (c) a polymerizablecomposition disposed between the surface of the mold and the surface ofthe substrate, wherein the polymerizable composition comprises: (i) abulk material; and (ii) a non-ionic surfactant having a first end and asecond end, wherein the first end of the non-ionic surfactant has anaffinity for the bulk material, and the second end of the non-ionicsurfactant is fluorinated.
 2. The imprint lithography mold assembly ofclaim 1, wherein the second end of the non-ionic surfactant in thepolymerizable composition is oriented toward the surface of the mold. 3.The imprint lithography mold assembly of claim 1, wherein the non-ionicsurfactant has the following formula:F(CF₂CF₂)_(x)CH₂CH₂O(RO)_(y)R′ wherein (RO)_(y) is a poly(oxyalkylene)group that includes groups having two to four carbon atoms, R′ is aterminal group of H or C₁ to C₄ alkyl, and x and y are integers.
 4. Theimprint lithography mold assembly of claim 3, wherein R is selected fromthe group consisting of —CH₂CH₂—, —CH₂CH₂CH₂—, —CH(CH₃)CH₂—, and—CH(CH₃)CH(CH₃)—.
 5. The imprint lithography mold assembly of claim 3,wherein R′ is selected from the group consisting of H and methyl.
 6. Theimprint lithography mold assembly of claim 1, wherein the non-ionicsurfactant has the following formula:

wherein R and R′ are identical or different and selected from the groupconsisting of H and methyl; wherein R″ is an optional sulfonyl linkinggroup —SO₂N(R′″″), with R′″″ selected from the group consisting of C₁ toC₆ alkyl; wherein (OR′″)_(z) is a poly(oxyalkylene) group comprising atleast one type of oxyalkylene unit; wherein R″″ is a terminal groupselected from the group consisting of H, methyl, and C₁ to C₄ alkyl; andwherein the ratio of x to y is in a range of 1:1 to 3:1.
 7. The imprintlithography mold assembly of claim 6, wherein the ratio of x to y is ina range of 1:1 to 2:1.
 8. The imprint lithography mold assembly of claim1, wherein the non-ionic surfactant has the following formula:

where x is an integer in a range of 0 to 6, inclusive; and y is aninteger in a range of 0 to 15, inclusive.
 9. The imprint lithographymold assembly of claim 1, wherein the non-ionic surfactant has thefollowing formula:

where x is an integer having a value of 1 to 2; y is an integer having avalue of 2 to 1; and z is an integer having a value in a range of 0 to6, inclusive.
 10. The imprint lithography mold assembly of claim 1,wherein the non-ionic surfactant includes a silicon atom.
 11. Theimprint lithography mold assembly of claim 1, further comprising alamella between the surface of the mold and the bulk material, whereinthe lamella comprises the second end of the non-ionic surfactant. 12.The imprint lithography mold assembly of claim 11, wherein the secondend of the non-ionic surfactant is in contact with the surface of themold.
 13. The imprint lithography mold assembly of claim 1, furthercomprising one or more additional surfactants.
 14. The imprintlithography mold assembly of claim 13, wherein the one or moreadditional surfactants are selected from the group consisting of ionic,non-ionic, cationic, and zwitterionic surfactants.
 15. The imprintlithography mold assembly of claim 13, wherein one of the additionalsurfactants is selected from a group consisting of a silicon-containingsurfactant, a hydrocarbon-based surfactant, and a fluorinatedsurfactant.
 16. The imprint lithography mold assembly of claim 13,wherein the polymerizable composition further comprises an initiator.17. The imprint lithography mold assembly of claim 13, wherein the bulkmaterial comprises one or more compounds selected from the groupconsisting of vinyl ethers, methacrylates, acrylates, thiolenes, andepoxies.
 18. The imprint lithography mold assembly of claim 1, wherein aviscosity of the polymerizable material is in a range of about 0.5 cpsto about 20 cps.
 19. The imprint lithography mold assembly of claim 1,wherein a viscosity of the polymerizable material is in a range of about10 cps to about 500,000 cps.
 20. The imprint lithography mold assemblyof claim 1, wherein a viscosity of the polymerizable material is in arange of about 10 cps to about 20,000 cps.